Alternative RNA degradation pathways by the exonuclease Pop2p from Saccharomyces cerevisiae

Sequence effects on exonuclease activity of Pop2p. (A) Representative PAGE for an exonuclease reaction of Pop2p (1000 nM) with U₃₆ and C₃₆ (1 nM). Aliquots were removed at 10, 20, 40 sec, 1, 5, 10, 15, 20, and 25 min. (B) Observed rate constants (removal of first nucleotide) for degradation of C₃₆ and U₃₆ as a function of Pop2p concentration. Data for A₃₆ are given for comparison. Error bar represents the standard error from fitting time courses to rate equations. (C) Processivity values of Pop2p for U₃₆ and C₃₆ (data for A₃₆ are given for comparison). Data points represent an average of three independent experiments, error bars show one standard deviation. Numbers indicate the average number of steps. (D) Representative PAGE for an exonuclease reaction of Pop2p (1000 nM) with A₂₆C₁₀ and C₂₆A₁₀. Aliquots were removed at 10, 20, 40 sec, 1, 5, 10, 15, 20, and 25 min. (E) Observed rate constants (removal of first nucleotide) for degradation of A₂₆C₁₀ and C₂₆A₁₀ as a function of Pop2p concentration. Error bar represents the standard error from fitting time courses to rate equations. (F) Processivity values of Pop2p for A₂₆C₁₀ and C₂₆A₁₀. Data points represent an average of three independent experiments, error bars show one standard deviation. Numbers indicate the average number of steps.